Arguably he has the biggest challenge since Patrick Troughton took over from William Hartnell in 1966. Back then, Hartnell had taken the role and moulded it around him in the first three years of the show. Producers had no idea if the 'changing face' concept would be accepted by the viewer. Troughton not only took on the challenge but also set the template of difference for every actor to follow him.

While there has already been a regeneration in the new series (David Tennant taking over from Christopher Eccleston), Eccleston was always going to a one year Doctor – and the show was not part of the national psyche.

Now it is, Tennant is everywhere, and Matt Smith is going to have to step into his shoes, be totally different, totally the same, and endure the intense media pressure that the role will bring upon him.

His age is going to be the first point of potential criticism. At 26 he is the youngest actor to take on the role. Peter Davison was 29 when he took over from Tom Baker. Smith's CV includes two Laurence Oliver Awards, the role of Danny Foster in BBC's Party Animals, and the obligatory appearance with Billie Piper in Ruby and the Smoke.

Smith's casting is also the first visible choice from Stephen Moffatt, who is taking over from Russell T. Davis as the Executive Producer / Show Runner of the BBC's flagship show.

David Tennant returns to our screens as the tenth Doctor at Easter, while Matt Smith will start filming this summer to be on our screens in the spring of 2010.